Pump device

ABSTRACT

A pump device for delivering fluid to be pumped includes at least one drive unit with a drive and at least one receiving region on which at least two pump cartridges can be positioned so as to be hydraulically connected in series.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a U.S. National Phase Patent Application of PCT Application No.: PCT/EP2017/065310, filed Jun. 21, 2017, which claims priority to German Patent Application No. 10 2016 111 406.5, filed Jun. 22, 2016, German Patent Application No. 10 2016 111 414.6, filed Jun. 22, 2016, German Patent Application No. 10 2016 111 419.7, filed Jun. 22, 2016, German Patent Application No. 10 2016 111 427.8, filed Jun. 22, 2016, German Patent Application No. 10 2016 111 440.5, filed Jun. 22, 2016, German Patent Application No. 10 2016 111 445.6, filed Jun. 22, 2016, and German Patent Application No. 10 2016 111 408.1, filed Jun. 22, 2016, each of which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The invention relates to a pump device to deliver a fluid, for example out of a borehole.

BACKGROUND OF THE INVENTION

Owing to the wide variety of different points of use and use parameters, for example delivery volume and pressure to be overcome and the frequently very limited installation space available, a wide variety of pump devices is required. Such pump devices are for example used as borehole pumps. Depending on the requirements for the pump and the pump capacities, a number of pump stages are required depending on the use. For this reason, the drive shaft usually has to be mounted between the pump stages on many pumps to be able to ensure safe operation of the pump device. This, in turn, leads to an exact sequence of pump elements and bearings having to be maintained during the installation of the pump device which can only be ensured with sufficient safety under controlled conditions.

In the case of known pump devices, the electrical supply means is guided from the connecting section along an outer wall of the pump device up to the drive, whereby the installation space available for the actual pump device is limited.

SUMMARY OF THE INVENTION

The object of the invention is to provide a pump device in the case of which available installation space is optimally utilised.

The object is achieved according to the invention in the case of the pump device mentioned at the outset by virtue of the drive shaft being or comprising a hollow shaft and the electrical supply means running inside the drive shaft.

As a result, the electrical supply means does not have to be guided outside on a wall of the pump device. An improved use of space therefore results, for example in the case of pump devices provided for boreholes, on the one hand because when the electrical supply means is guided along the outside, the entire circumference is generally not used and therefore space is reduced by a non-circular configuration of the pump device and, on the other hand, as a result of the effect of a pump element and the capacity of a drive generally increasing square with the radius of the respective device.

A higher pump capacity of the pump device can be achieved when installation space is provided for the electrical supply means in proximity to the axis, as in this case inside the hollow shaft, since the pump capacity and the drive capacity achievable in this region is low.

A motor controller that is possibly provided can also be arranged behind the drive viewed from the connecting section such that the motor controller can be positioned outside of the flow path of the fluid to be pumped.

An advantageous solution envisages a motor controller and an electric connection of the pump device being electrically connected to one another by the electrical supply means. As a result, the transfer of the electric energy inside the pump device can be guided from the supply to the consumer.

Control signals transmitted to the pump device can also be relayed to the motor controller.

A particularly advantageous possibility envisages the electric connection of the pump device being arranged in the connecting section. A fluid line and an electric power supply device can thus be laid from the same region of the pump device which leads to a further space saving.

An advantageous possibility envisages the electrical supply means extending from the connecting section through the pump element and through an electric motor of the drive. This is advantageous since both the pump element and the electric motor are more effective when the electrical supply means runs inside the drive shaft than if it were to run outside.

A convenient solution envisages the at least one pump element comprising an impeller. Since an impeller is a pump element, which functions on the principle of flow pumps, valves or flaps are not required. Moreover, in the case of an impeller, the effectiveness is dependent on the distance to the rotational axis of the impeller such that the effect of the central guide of the electrical supply means comes into play.

A particularly favourable possibility envisages the connecting section comprising a central fluid discharge opening on which a hose or pipe connection is fixable or fixed into which the fluid to be pumped can be introduced. In this manner, the fluid to be pumped can be introduced into a line through which the fluid to be pumped can be guided to the target location.

A particularly advantageous solution envisages a central anchor being arranged inside the hollow shaft and coaxially to the hollow shaft and the electrical supply means running in a clearance between the central anchor and the hollow shaft. This is advantageous since it is unproblematic for the electric properties when an electrical conductor is designed flat and by means of this arrangement of central anchor and electrical supply means inside the hollow shaft, a configuration of the central anchor that is advantageous for the stability of the central anchor is possible.

For optimal utilisation of the tubular clearance between the central anchor and the hollow shaft, it is advantageous for an electrical conductor of the electrical supply means to be arranged uniformly around the anchor in the circumferential direction. In particular, at least two electrical conductors are provided.

A particularly favourable solution envisages an electrical conductor of the electrical supply means having a circular arc-segmented cross section. The circular-arc segmented cross section of an electrical conductor means it is optimally adapted to the limited installation space inside the hollow shaft.

A favourable possibility for the transmission of electric energy envisages an electrical conductor of the electrical supply means being electrically insulated at least inside the drive shaft.

For mechanical stability of an electrical conductor, it is favourable for an inner insulating layer to be arranged between electrical conductors of the electrical supply means and the central anchor since in this manner the electrical conductors can be arranged over the insulating layer supported on the central.

A further favourable possibility envisages an outer insulating layer being arranged between electrical conductors of the electrical supply means and the hollow shaft which does not contact the hollow shaft. The electrical conductors are therefore electrically insulated around their entire circumference inside the hollow shaft. Since the insulating layer does not contact the hollow shaft, this insulating layer is not damaged and mounting and/or lubricating is not required at this point.

A further advantageous possibility envisages an electrical conductor of the electrical supply means being electrically connected to the electric connection of the pump device inside the connecting section by contact fingers. Contact of the electrical conductors of the electrical supply means can thus be achieved by inserting the connecting section.

A particularly favourable solution further envisages the electrical supply means running inside a tube, which runs inside the hollow shaft. As a result, an electrical conductor of the electrical supply means is guided through the tube such that no undesired contact, for example with the hollow shaft, can occur. Therefore the electrical conductors of the electrical supply means themselves do not have to have any particular mechanical stability such that the electric properties of the electrical supply means and electrical conductors, for example in the case of the material selection, can have priority.

A particularly advantageous solution also envisages the electrical supply means being guided through the centre of the drive shaft and the drive shaft having a hollow shaft. The advantage of this solution is that the pressure that can be generated by an impeller increases square with the diameter of the impeller such that an increase in the diameter of the drive shaft causes a smaller loss than the loss that would be caused by the reduction in the diameter of the impeller.

A further advantage is that the increase in the diameter of the drive shaft causes a smaller reduction in a motor capacity than the reduction of the outer diameter of an electric motor.

The object of the invention is further to provide a pump device of the type mentioned at the outset in the case of which the mounting of the rotating elements of the pump device is less complex.

The object is achieved in the case of the pump device mentioned at the outset according to the invention by at least one second pump element to generate a pressure differential, wherein the first pump element and the second pump element are arranged in relation to one another and designed such that an axial thrust, which acts on the first pump element when the pressure differential is generated, is opposed to an axial thrust, which acts on the second pump element when the pressure differential is generated.

The axial thrusts can therefore be wholly or partially offset by this arrangement of the pump elements.

A particularly advantageous possibility envisages the first pump element having a first impeller with a suction nozzle and the second pump element having a second impeller with a suction nozzle and the suction nozzle of the first impeller facing one another and in particular being arranged or pointing in opposing directions. This is advantageous since the direction of the axial thrust, which acts on an impeller, is determined by the direction in which the suction nozzle of an impeller is arranged.

A further advantage is when an impeller is a pump element which functions on the principle of flow pumps. Valves or flaps are then not required.

The axial forces, which have to be absorbed by the mounting of the pump elements, can be reduced.

As a result, the first pump element and the second pump element are arranged coaxially to one another, the axial forces directed against one another, which act on the first pump element and on the second pump element, do not generate any torque, which is advantageous for compensating the axial forces.

A favourable possibility envisages the second pump element being designed and arranged substantially mirror-symmetrically to the first pump element. As a result, the axial forces, which act on the first pump element, and the axial forces, which act on the second pump element, are substantially equal in size, whereby the axial forces can be virtually completely compensated.

An advantageous possibility envisages the first pump element and the second pump element being fixed against one another at least in the axial direction. The axial forces, which act on the first pump element and on the second pump element, are coupled together by this fixing in the axial direction, whereby these forces can be offset.

A particularly favourable possibility envisages an inner sleeve on which the first pump element and the second pump element are fixed in a torque-proof manner in the axial direction. As a result, both the rotation of the first pump element and the second pump element is coupled along with the axial forces, which act on the first pump element and on the second pump element. The axial forces, which also act on the first pump element, and the axial forces, which act on the second pump element, are substantially equal due to the coupling of the rotation such that the axial forces are virtually completely offset.

A favourable solution envisages the first pump element being arranged in a first pressure generation region, which has an axial suction opening and the second pump element being arranged in a second pressure generation region, which has an axial suction opening and the axial suction opening of the first pressure generation region and the axial suction opening of the second pressure generation region being directed in opposing directions.

The position of the axial suction openings relative to the pump elements determines the direction of the axial forces, which act on the pump element. Since the axial suction opening of the first pressure generation region and the axial suction opening of the second pressure generation region are directed in opposing directions, it can be ensured that the first pump element and the second pump element arranged opposite thereto are flowed through uniformly such that the axial forces, which act on the first pump element, and the axial forces, which act on the second pump element, act substantially equally and in opposing directions.

A particularly favourable solution envisages the first pressure generation region and the second pressure generation region being arranged adjacent to one another and the axial suction openings being arranged at sides of the pressure generation regions facing one another. This allows the two pump elements to be flowed through in an identical manner. It also ensures that a space-saving arrangement of the first pressure generation region and of the second pressure generation region is achieved.

An advantageous solution envisages the first pressure generation region being delimited outwards in the radial direction by a first radial partition wall, which has at least one output opening of the first pressure generation region. Fluid to be pumped, which flows through the pressure generation region, can thus leave said pressure generation region through the output openings in the radial direction such that no further axial forces are generated on the pump element by the outflowing of the pumping fluid.

A particularly advantageous solution envisages the at least one output opening establishing a fluidically-effective connection from the first pressure generation region to a fluid passage, which fluidically-effectively connects the at least one output opening of the first pressure generation region to the axial suction opening of the second pressure generation region. A hydraulic series connection of the first pump element to the second pump element can thus take place, whereby the achievable pressure differential of the pump device is given by the achievable pressure differentials of the individual pump elements.

A particularly advantageous solution envisages at least one first fluid channel extending from the at least one output opening of the first pressure generation region to a return region. The first fluid channel therefore forms a first part of the fluid passage.

For the integration of further fluid channels, it is advantageous for the extension of the first fluid channel to be delimited in the circumferential direction and to be delimited outwards in the radial direction by a cylindrical outer wall of the pump device and inwards by the first radial partition wall and a second radial partition wall.

Since the first fluid channel is delimited in the circumferential direction, it is possible to arrange additional fluid channels offset in the circumferential direction which are not connected directly to the first fluid channel in fluidically-effective manner. This provides greater freedom in relation to the arrangement of individual regions in the pump device.

An advantageous solution for an equivalent effect of the first pump element and the second pump element envisages the second pressure generation region being delimited outwards in the radial direction by a second radial partition wall, which has at least one output opening of the second pressure generation region.

A further favourable solution envisages at least one second fluid channel extending from the at least one output opening of the second pressure generation region to a return region and outlet region. After it has run through the second pressure generation region, the fluid to be pumped can thus be guided to an outlet opening.

A further particularly favourable solution envisages the at least one second fluid channel being delimited in the circumferential direction and the at least one second fluid channel being arranged in the circumferential direction offset to the at least one first fluid channel. In this manner, both the first fluid channel and the second fluid channel can run independently of one another in a region radially outside the first pressure generation region and the second pressure generation region.

An additional particularly advantageous solution envisages a (uniform) pump cartridge in which the at least one first pump element and the at least one second pump element are arranged. The combination of the first pump element and the second pump element in a single pump cartridge allows one unit to be produced in the case of which the axial forces acting on the pump elements are compensated such that an axial mounting of the first pump element and the second pump element has to withstand only proportionally low forces in the axial direction.

An additional advantageous possibility envisages the pump cartridge having at least one first section in which a first pressure generation region is arranged, having a second section in which a second pressure generation region is arranged, having a third section in which a return region is arranged and having a fourth region in which a return and outlet region is arranged. In this manner, the advantages according to the invention can be achieved by the pump cartridge.

The object of the invention is also to provide a pump device of the type mentioned at the outset in the case of which the mounting of the pump device is simplified.

The object is achieved in the case of the pump device mentioned at the outset according to the invention by virtue of the drive shaft being or having a hollow shaft, the at least two pump elements being connected to the drive shaft in a torque-proof manner in a first region and the drive shaft being mounted in a second region of the drive shaft which is different to the first region.

The use of a hollow shaft leads to greater stiffness of the drive shaft, whereby it no longer has to be mounted between the individual pump elements such that the mounting of the drive shaft outside of the pump elements is adequate.

Since the mounting of the drive shaft is mounted in a region that is different to the region in which the at least two pump elements are connected to the drive shaft in a torque-proof manner, the installation sequence of the pump elements and of the bearings is simplified such that installation in an incorrect sequence can be ruled out. As a result, the installation of the pump device is possible directly at the point of use.

A favourable solution envisages the hollow shaft being mounted at two points. In this manner, the drive shaft can be mounted adequately with a smaller number of bearings such that both the installation is easier and also the costs for the individual bearings can be saved.

An advantageous solution envisages the hollow shaft extending from a drive section of the pump device to a connecting section of the pump device. As a result, the hollow shaft can be integrally designed, which further increases the bending stiffness of the drive shaft.

A particularly favourable solution envisages the hollow shaft being mounted in the connecting section of the pump device. As a result, the bearing of the hollow shaft impedes the fluid flow inside the pump device to a lesser extent than if the bearing were arranged between two pump elements. In this way, the hollow shaft is also mounted in proximity to the end of the hollow shaft, whereby the bearing can better absorb torques which act at the hollow shaft transverse to the rotational axis of the hollow shaft.

A particularly favourable possibility envisages the hollow shaft being mounted in the drive section of the pump device. Less obstruction to the fluid flow results here since the mounting of the drive shaft is arranged in a region of the pump device through which the fluid to be pumped does not flow. Moreover, the mounting of the hollow shaft is also arranged in the region of the end of the hollow shaft such that the absorption of torques, which are applied transverse to the rotational axis of the hollow shaft, can be better absorbed.

It is favourable for the mounting of the hollow shaft for the pump device to have a first mounting device which mounts the hollow shaft and a fixing and mounting device (second mounting device) which mounts the hollow shaft.

A favourable solution envisages the first mounting device having at least one radial ring bearing by means of which the hollow shaft is mounted. This radial mounting prevents the hollow shaft from tilting.

An additional particularly favourable solution envisages the at least one first radial ring bearing being arranged inside an electric motor of the drive. As a result, the hollow shaft can be used both as a drive shaft of the pump device and as a drive shaft of the electric motor. Likewise, the first radial ring bearing acts as a bearing for the pump device and an electric motor of the drive.

It is favourable for the stability of the position of the hollow shaft for the fixing and mounting device to have at least one radial ring bearing by means of which the hollow shaft is mounted.

It is favourable for the installation of the pump device for the at least one radial ring bearing of the fixing and mounting device to be located inside a support section of the fixing and mounting device, which is arranged in the connecting section of the pump device, since in this manner the radial ring bearing is installed together with the support section of the fixing and mounting device. Thus, the radial ring bearing also cannot be accidentally inserted prematurely, i.e. between the pump elements.

A particularly favourable possibility also envisages the drive having a motor, the rotational speed of which is independent of a mains frequency. The rotational speed of the drive can thus be greater than the mains frequency of for example 50 hertz. This is advantageous since the achievable delivery head for each impeller is dependent both on the diameter of the impeller and on the rotational speed of the impeller. In this manner, the number of impellers required can thus be reduced.

A particularly advantageous solution also envisages the drive having an electronically commuted synchronous motor. Such electric motors have a high degree of effectiveness, are easy to control and allow high rotational speeds.

It is particularly favourable for a rotor of the electric motor of the drive to be held on the hollow shaft. As a result, a direct coupling between drive and hollow shaft is achieved such that losses caused, for example by a coupling, can be avoided.

For the direct coupling of the drive to the hollow shaft, it is favourable for the rotor of the electric motor of the drive to be held on the hollow shaft by a connection section.

It is particularly advantageous for the rotor of the electric motor of the drive to be held only on the hollow shaft since a separate mounting of the rotor is therefore not necessary and it is guided through the hollow shaft.

It is favourable for the application of the pump device inside a borehole for this “small” diameter to have; as a result, the pump device can also be inserted into boreholes that are not completely straight. The pump device, in the case of smaller diameters, does not have to be operated at higher rotational speed (in comparison to a pump device with a larger diameter) in order to achieve the same delivery head.

An advantageous solution also envisages the drive shaft being supported only by two radial bearings, which are arranged outside of the region of the impellers.

A particularly favourable possibility also envisages the drive having a high rotational speed such that the number of impellers can be reduced such that the drive shaft does not require any support between the impellers.

An additional particularly advantageous possibility envisages the drive shaft being integrally formed from the drive to the impellers such that the two bearings are adequate for mounting the hollow shaft.

An additional advantageous possibility envisages a hollow shaft, which has a higher bending stiffness than conventional shafts.

Such an arrangement enables the installation of the pump device at the point of use without the danger of installation faults since all pump stages look the same.

Known pump devices also have the disadvantage of having to be installed in a workshop environment since, during operation, significant forces occur by pumping, which attempt to pull the pump device apart. Connections to the pump device have to withstand large forces such that a workshop environment is required for the manufacture.

Therefore, the object underlying the present invention is to provide a pump device of the type mentioned at the outset, which can be more easily installed.

This object is achieved according to the invention in the case of the pump device mentioned at the outset by virtue of the drive shaft being or comprising a hollow shaft and the pump device having an anchor to absorb axial forces, which runs through the hollow shaft.

Since the anchor runs through the hollow shaft, axial forces can be directed through the centre of the pump device. Since the pump capacity depends on the square of the distance to the axis, the forces are therefore directed through a region in which the pressure generation is relatively low such that the measures for absorbing the axial forces have less of an influence on the pump capacity.

An outer wall of the pump device also does not have to transfer forces or has to transfer minor forces such that threads are not required in the outer wall for force transfer, which would have a large diameter and for which special tools would be required for installation. In addition, flare connections can be avoided, which have to transfer large forces and would therefore be complex to manufacture.

By using an anchor, the pump device can be installed on-site at the point of use since no special tools or machines are required to install the pump device.

A favourable possibility envisages the anchor being designed to absorb pump forces, which occur during operation when pressure is generated. The size of the pump forces is substantially given by the generated pressure differential multiplied by the cross-sectional area of the pump device.

Since the central anchor is designed to absorb pump forces that occur when pressure is generated, the outer wall does not have to transfer any forces or has to transfer minor forces.

It is favourable for the anchor to be arranged coaxial to a rotational axis of a pump element, wherein the pump element serves to generate a pressure differential. In this manner, bending torques, which act on the anchor, can be reduced.

An additional favourable possibility envisages the anchor being designed in a rod shape. A rod-shaped anchor provides the highest tensile stability in the case of a given maximum diameter.

An advantageous possibility envisages the anchor extending from a connecting section through the pump element and through an electric motor of the drive. The pump device is held on the connecting section in particular by a hose or a tube. Since the anchor extends from the connecting section through the pump element and through the electric motor, it can absorb forces and transfer them to the connecting section. The forces occur in regions on the pump device in which the pump element and/or the electric motor are arranged.

An additional advantageous possibility envisages a pump element comprising or being an impeller. If an impeller is a pump element, which functions on the principle of flow pumps, valves or flaps are not required. Moreover, in the case of an impeller, the effectiveness is dependent on the distance to the rotational axis such that the effect of the central arrangement of the anchor and therefore the guidance of the forces fully comes into play.

A particularly favourable possibility envisages the anchor connecting the drive unit to a connecting section in a force-effective manner. The term force-effective is understood in the description and the accompanying claims as forces, in particular axial tensile forces being transferable. Since the anchor connects the drive unit to the connecting section in a force-effective manner, the pump device is held together and pump forces can be absorbed and directed away by the anchor.

A particularly advantageous possibility envisages the anchor being held on a connecting section by a detachable connection. Uninstallation of the pump device is thus possible, which is advantageous for example in the case of repairs to the pump device.

A solution favourable for holding the pump device together envisages the detachable connection of the anchor to the connecting section being capable of absorbing and absorbing forces at least in one direction.

An additional favourable solution envisages a connecting section comprising a fixing and mounting device with a support section and the anchor extending through the support section and the anchor having a securing section, which protrudes over the support section. In this manner, the support section can be engaged behind in order to allow a force-effective connection.

An advantageous solution envisages the securing section of the anchor having a thread. A thread enables a simple and stable connection.

An advantageous solution envisages a fastening element by means of which the securing section is held. Possible fastening elements are based in particular on a force-fit connection, materially-bonded connection, positive-locking connection or similar. For example, fastening elements comprise bolt, screw or adhesive connections. This is advantageous since the fastening element engages behind the support section so that the anchor cannot be pulled out of the support section. A force-effective connection emerges, as a result, at least for tensile forces.

An additional advantageous solution envisages the fastening element having or being a nut, in particular a retaining nut, which is screwable and/or screwed on the securing section of the anchor. On the one hand, this is advantageous since a nut can be installed easily and, on the other hand, the diameter of the nut is greater than the diameter of the securing section such that a recess is formed, which can engage and/or engages behind the support section.

A particularly advantageous solution envisages the drive unit comprising a drive section, which has a base section on which the anchor is held. Forces can be directed to the anchor through the base section.

The anchor is for example held on the base section by positive-locking connection, materially-bonded connection or similar.

The object underlying the invention is further to provide a pump device, which has optimal cooling of the drive.

This object is achieved according to the invention in the case of the pump device mentioned at the outset by virtue of the electric motor being arranged in a region filled with a coolant, said region comprising a coolant circuit, by the coolant circuit having at least one branch, which extends at least in sections along the outer wall of the pump device and by a coolant circulation in the coolant circuit being driven during the operation of the electric motor.

Since the coolant is guided at least in sections along the outer wall of the pump device, the coolant can dissipate heat to the environment of the pump device. This is, in particular, very effective in the case of a pump device, which is immersed into the fluid to be pumped, since the heat can therefore be dissipated very effectively via the outer wall of the pump device to the fluid to be pumped.

It is advantageous for the electric motor to have a rotor and for the coolant circulation in the coolant circuit to be driven by the rotation of the rotor. As a result, effective cooling can be achieved without additional coolant pumps.

A favourable possibility envisages the coolant circuit having at least one branch, which extends at least partially along the windings of the motor. The coolant can thus effectively absorb the waste heat occurring in the electric motor.

An additional favourable possibility envisages the electric motor having a rotor (internal rotor or external rotor), which has at least one bore which provides a fluidically-effective connection from an interior of the electric motor to an exterior of the electric motor. Electric motors with a bell-shaped rotor are so-called external rotor motors, which have a particularly high power density and are particularly difficult to cool due to the bell-shaped rotor. Due to the bore in the rotor, which causes a fluidically-effective connection from an interior of the motor to an exterior of the electric motor, the coolant can transport the waste heat of the electric motor through the rotor and therefore achieve effective cooling of the electric motor.

A particularly favourable solution envisages the pump device having at least one radial ring bearing, which is arranged inside the region filled with coolant. In this manner, the radial ring bearing can be cooled and lubricated by the coolant.

An additional advantageous solution envisages the coolant circuit having at least one branch, which extends along the at least one radial ring bearing at least in sections. As a result a circulation of the coolant is achieved along the radial ring bearing, whereby particularly good lubrication and cooling of the radial ring bearing is achieved.

A particularly advantageous solution envisages the pump device having at least two radial ring bearings and in each case at least one branch of the coolant circuit extending at least partially along the at least two radial ring bearings. This allows the coolant to be circulated along both radial ring bearings, whereby good cooling and lubrication of the two radial ring bearings can be achieved.

A particularly favourable possibility envisages the pump device having a drive shaft for torque transfer between the drive and the at least one pump element for generating a pressure differential, which is designed as a hollow shaft or has a hollow shaft. Hollow shafts have, in the case of identical weight, greater stiffness than shafts which are designed solidly.

An advantageous possibility envisages the coolant circuit having at least one branch which extends at least in sections inside of the hollow shaft. As a result, the coolant can be used inside the pump device and outside of the drive for example for cooling or lubrication.

An additional advantageous possibility envisages the hollow shaft having at least one bore, which provides a fluidically-effective connection from an interior of the hollow shaft to an exterior of the hollow shaft. The coolant circuit can be directed in a targeted manner by the bore to the points where cooling or lubrication is required.

A particularly advantageous possibility envisages at least one bore being arranged in the hollow shaft inside the electric motor. In this manner, the circulation of the coolant inside the electric motor can be adapted such that the regions in which the most waste heat occurs can be adequately cooled.

A favourable solution envisages the electric motor having a rotor with a connection section by means of which the rotor is held on the hollow shaft, the connection section having at least one bore and the hollow shaft having at least one bore, which is arranged aligned with the at least one bore in the connection section. As a result, the coolant can enter from an interior of the hollow shaft through the connection section into a region outside of the rotor of the electric motor and be directed from there for example to the outer wall of the pump device.

An additional favourable solution envisages at least one bore being arranged in the hollow shaft inside a first radial ring bearing, which is arranged inside the drive. Since the at least one bore is arranged inside the one first radial ring bearing, the coolant can be guided directly to this radial ring bearing, whereby it can be lubricated by the coolant (with lubricating function).

It is favourable for the mounting of the hollow shaft for the pump device to have at least one second radial ring bearing by means of which the hollow shaft is mounted against a tube arranged in the hollow shaft and for the tube to have at least one bore, which provides a connection from an interior of the tube to an exterior of the tube. Since the second radial ring bearing mounts the hollow shaft against the tube, which is arranged inside the hollow shaft, the second radial ring bearing can be arranged in a region filled with the coolant and also arranged outside of the drive. Since the tube has at least one bore, which provides a connection from an interior of the tube to an exterior of the tube, the coolant can be delivered through the tube inside the pump device in a targeted manner to points where the coolant is required.

In terms of the lubrication of the second radial ring bearing, it is advantageous for the tube to have at least one bore, which, viewed from the drive, is arranged behind the second ring bearing since in this manner the coolant must flow past the radial ring bearing and therefore can cool and lubricate the second radial ring bearing.

It is favourable for the pump device to be designed as a borehole pump or to comprise a borehole pump. Since a borehole pump is intended for use in a borehole, the pump device is immersed in the fluid to be pumped during operation, whereby the cooling is particularly effective via the outer wall of the pump device. Good cooling is also particularly effective in the case of a borehole pump, since the dissipation of the waste heat of the drive is particularly problematic owing to the restricted space conditions inside the borehole.

In the case of pump devices, bearings, by means of which the drive shaft is mounted, can in principle come into contact with the fluid to be pumped. Fluid to be pumped can contain particles which can lead to increased wear in the case of the bearings and the drive shaft.

The object underlying the invention is to reduce the stress on the bearings in the pump device mentioned at the outset.

This object is achieved according to the invention by virtue of the electric motor being arranged in a region filled with a coolant, which comprises a coolant circuit, wherein during operation of the electric motor coolant circulation is driven, the drive shaft being designed as a hollow shaft or having a hollow shaft and the pump device having at least one radial ring bearing on which the drive shaft is mounted and which is arranged inside the region filled with coolant.

Since the drive shaft is designed as a hollow shaft or comprises a hollow shaft, the drive shaft has high stiffness whereby the number of bearings can be reduced. Since the pump device has at least one radial ring bearing, by means of which the drive shaft is mounted and which is arranged inside the region filled with coolant, the radial ring bearing does not come into contact with the fluid to be pumped such that the wear on the radial ring bearing can be reduced.

The coolant can also contain constituents, which can be used for lubrication.

A favourable possibility envisages all radial ring bearings on which the hollow shaft is mounted being arranged inside the region filled with coolant. Good lubrication and cooling of all radial ring bearings can then be ensured. These radial ring bearings are also protected from increased wear and tear by particles, which could be contained in the fluid to be pumped.

An additional favourable possibility envisages the coolant circuit having at least one branch, which extends at least in sections along the radial ring bearing. In this manner, the coolant can also be circulated at the radial ring bearing such that good lubrication and good cooling of the radial ring bearing is ensured.

A particularly favourable possibility envisages the pump device having at least two radial ring bearings and in each case at least one branch of the coolant circuit extending at least partially along the at least two radial ring bearings. The drive shaft can be easily mounted with two radial ring bearings. Since at least one branch of the coolant circuit extends along each of the at least two radial ring bearings, these radial ring bearings can be adequately lubricated and cooled.

An advantageous possibility envisages the coolant circuit having at least one branch which extends at least in sections inside of the hollow shaft. Since a branch of the coolant circuit extends inside the hollow shaft, the coolant can be directed in a targeted manner inside the pump device.

An additional advantageous possibility envisages the hollow shaft having at least one bore, which provides a fluidically-effective connection from an interior of the hollow shaft to an exterior of the hollow shaft. As a result, the coolant can be directed in a targeted manner at a certain point into the hollow shaft or out of the hollow shaft in order to distribute the coolant as required.

A particularly advantageous possibility envisages at least one bore being arranged in the hollow shaft inside a first radial ring bearing, which is arranged inside the at least one drive. The radial ring bearing, which is arranged inside the at least one drive, can thus be adequately supplied with coolant for lubrication and for cooling.

A favourable solution envisages the pump device having at least one second radial ring bearing on which the hollow shaft is mounted against a tube arranged in the hollow shaft and the tube having at least two bores, which provide a connection from an interior of the tube to an exterior of the tube. As a result, the bearing is located inside the hollow shaft, whereby the second radial ring bearing is arranged in a region filled with the coolant. The tube, which is arranged inside the hollow shaft, can also be used to direct the coolant inside the pump device.

An additional favourable solution envisages the second radial ring bearing, viewed from the drive, being arranged behind the pump element. In this manner, a second bearing point is achieved for the hollow shaft, which is spaced from the first bearing point so that the shaft is adequately secured against tilting.

A particularly favourable solution envisages the tube having at least two bores, which, viewed from the drive, are arranged behind the two radial ring bearings and/or inside the second radial ring bearing. This ensures that the second radial ring bearing is adequately supplied with coolant for cooling and lubrication.

An advantageous solution envisages the coolant circuit having a branch, which extends at least in sections inside of the tube. The coolant circuit can be closed in this manner since for example the coolant flows inside the tube away from the drive in the direction of a connecting section and flows back outside of the tube, but inside of the hollow shaft.

An additional advantageous solution envisages the coolant circuit having at least one branch, which extends along the outer wall of the pump device at least in sections. The coolant can thereby effectively dissipate waste heat to the environment of the pump device.

A particularly advantageous solution envisages the electric motor having a rotor with a connection section by means of which the rotor is held on the hollow shaft, the connection section having at least one bore and the hollow shaft having at least one bore, which is arranged aligned with the at least one bore in the connection section. A branch of the coolant circuit can thereby be guided outside along the rotor of the motor, whereby it can extend up to and along the outer wall of the pump device.

It is further favourable for the electric motor to have an internal rotor or external rotor as the rotor, which has at least one bore, which provides a fluidically-effective connection from an interior of the electric motor to an exterior of the electric motor. As a result, the coolant, which absorbed waste heat in the electric motor, can transport the waste heat out of the electric motor and therefore ensure effective cooling of the electric motor.

It is advantageous for the electric motor to have a rotor and for the coolant circulation in the coolant circuit to be driven by the rotation of the rotor. As a result, effective cooling can be achieved without additional coolant pumps.

In terms of the cooling of the electric motor, it is also favourable for the coolant circuit to have at least one branch, which extends at least partially along the windings of the electric motor since the majority of the waste heat occurs in the windings of the electric motor.

The pump device is advantageously designed as a borehole pump or has a borehole pump. The advantages according to the invention can thereby be utilised particularly effectively since, owing to the restricted conditions inside the borehole, the cooling problem is significant and the fluid to be pumped often contains particles, such as for example sand.

It is further advantageous for the coolant to have water and glycol. A mixture of water and glycol has been proven as a combined coolant and lubricant.

Lastly, the object underlying the invention is to provide pump devices with less effort, which cover a large area of use and power range.

This object is achieved according to the invention by a construction kit for a pump device to deliver fluid, the construction kit at least comprising:

-   at least one drive unit with a drive and at least one receiving     region at which at least two pump cartridges can be positioned so as     to be hydraulically connected in series, -   a set of pump cartridges, each of which comprises a housing with a     first connecting side, which has a suction opening and a second     connecting side, which has an outlet opening, -   wherein at least two of the pump cartridges in the set of pump     cartridges have different pump capacities.

The advantage of this solution is that a large number of combinations of pump cartridges and drive units is possible with the set of pump cartridges and a wide spectrum of pump capacities can be provided.

Individual pump cartridges can thus be designed for different delivery volumes which then require weaker or stronger drive units. The achievable pressure can also be varied for example by the rotational speed of the drive unit.

A measurement for the pump capacity is a delivery head as the usable mechanical work transferred by a pump to a pumped liquid. The pump capacity can also be zero.

A favourable solution envisages a pump cartridge comprising at least one pump element arranged in the housing to generate a pressure differential between the suction opening and the outlet opening. At least one pump cartridge from the set of pump cartridges thus has a pump capacity different to zero.

An advantageous possibility envisages at least one pump element comprising an impeller. High pump capacities can be generated in a small space by means of impellers.

A particularly advantageous possibility envisages at least two pump cartridges in the set of pump cartridges having different pump capacities as a result of a distance between a first wall of the impeller and a second wall of the impeller being different in size, between which the fluid to be pumped is set into rotation. As a result, the active volume of the pump cartridge can be adapted by the fluid to be pumped being set into rotation such that the delivery volume and the required torque are variable.

A favourable possibility envisages the set of pump cartridges comprising an empty cartridge which does not have any pump element or pump capacity. The achievable pressure can be reduced by the pressure achieved by the pump cartridge by means of exchanging a pump cartridge with an empty pump cartridge and the required drive capacity can be reduced accordingly. A proportionally small number of different drive units and pump cartridges, which can each be interchanged with one another as desired, can therefore adapt the pump capacity to the requirements of most applications.

An advantageous solution envisages the drive unit having a drive shaft, which extends through the receiving region and at least one of the pump cartridges in the set of pump cartridges having an inner sleeve, which is slidable over the drive shaft of the drive unit. This simplifies the installation of the pump device since in the case of such a configuration the pump cartridges can be positioned on the receiving region of the drive unit.

A particularly advantageous solution envisages the inner sleeve being held in a torque-proof manner on the drive shaft. As a result, the drive capacity of the drive unit can be transferred via the drive shaft to the pump cartridge.

A favourable solution envisages the inner sleeve being held on the drive shaft by a positive-locking connection. Since the inner sleeve is held on the drive shaft by a positive-locking connection, a tool is not required when positioning the pump cartridge on the receiving region of the drive unit.

A particularly advantageous solution envisages the inner sleeve extending over the entire height of the respective pump cartridge. As a result, the inner sleeve of a further pump cartridge can be supported on the inner sleeve of the first pump cartridge such that the movability of the inner sleeve is delimited in the axial direction when the pump device is installed.

A favourable possibility envisages the set of pump cartridges comprising at least one pump cartridge that has a pump element which is held on the inner sleeve of the pump cartridge in a torque-proof manner and fixedly in the axial direction. As a result, the pump element is set into rotation by the rotation of the drive shaft and is fixed in the axial direction by the inner sleeve.

A particularly favourable possibility envisages the pump element generating a pressure differential between the suction opening and the outlet opening of the pump cartridge when it is set into rotation by the drive shaft. The pressure differential between suction opening and the outlet opening causes a flow of the fluid to be delivered such that the fluid can be delivered from the point of use of the pump device to a target site.

A further advantageous solution envisages the housing of at least one pump cartridge from the set of pump cartridges having an outer wall, which, when the pump cartridge is positioned in the drive unit, rests on the outer wall of the pump device. The installation space available can be optimally utilised in this manner. As a result, the pump cartridge is also fixed in the radial direction inside the pump device.

A particularly favourable solution envisages the first connecting side and the second connecting side of the pump cartridges from the set of pump cartridges being designed complementary to one another. This allows the pump cartridges to be stacked directly one on top of the other without additional connection elements.

It is also favourable for the first connecting side to have a sealing surface and for the second connecting side to have a sealing surface, which is arranged aligned with the sealing surface of the first connecting side in the axial direction. The sealing surfaces of the second connecting side of a first pump cartridge and the sealing surface of the first connecting side of a second pump cartridge, when the first pump cartridge and the second pump cartridge are positioned in a drive unit, can thus seal the transition between the first pump cartridge and the second pump cartridge.

An additional particularly advantageous solution envisages the first connecting side of at least one of the pump cartridges from the set of pump cartridges having an inlet-side base, which has a central opening, wherein the suction opening is formed in a circular shape in the central opening and the second connecting side of at least one of the pump cartridges from the set of pump cartridges having an opposing outlet-side base, which has a central opening, wherein the outlet opening is formed in a circular shape in the central opening. Since the suction opening and the outlet opening are located opposite one another, the achievable pressure of the pump device can be increased by stacking the pump cartridges.

An additional particularly advantageous solution envisages the outlet opening of a first pump cartridge from the set of pump cartridges, which is positioned at the receiving region, being arranged flush with the suction opening of a second pump cartridge from the set of pump cartridges, which is positioned at the receiving region. As a result, the flow cross-section of the fluid to be pumped is not further restricted by the size of the suction opening or the outlet opening since they are located exactly above one another.

It is favourable for the at least one drive unit to have a suction section, which is arranged between the drive and the at least one receiving region and in which an outer wall of the pump device has a plurality of suction holes through which fluid to be pumped can be suctioned into the pump device. In this manner, the drive can be arranged such that the drive is located in the region of the pump device through which flows the fluid to be pumped such that the cross-section provided in order to deliver the fluid to be pumped is not restricted by the drive.

A further particularly favourable solution envisages the receiving region of the at least one drive unit having a cartridge connection, which is designed complementary to the first connecting side of the pump cartridge from the set of pump cartridges. A pump cartridge from the set of pump cartridges can thus be positioned in the drive unit without additional connection elements and/or adapter elements being required.

A further particularly advantageous solution envisages the construction kit having at least two drive units, which have different drive capacities. The number of possible combinations of pump cartridges and drive units is thus increased such that the spectrum of pump capacities that can be achieved with a pump device is increased.

The drive capacity is understood in the description and the accompanying claims to mean in particular a rotational speed and a torque.

It is advantageous for the at least two drive units to have different motors. The motors substantially determine the drive capacity that the drive unit can provide. The motors can be different in particular in terms of the achievable rotational speed and achievable torque and therefore influence the achievable pressure and achievable delivery volumes.

In order to generate different drive capacities, it is favourable for the motors to have different stator heights and different rotor heights. In this manner, the active motor volume can be adapted without the diameter of the motors having to be adapted. This allows drive units to be provided with different drive capacities, but also substantially identical receiving regions.

A further particularly advantageous solution envisages a different number of pump cartridges from the set of pump cartridges being positionable in the receiving regions of at least two drive units. In this manner, the achievable pressure of the pump device can in particular be varied.

The above-mentioned object is also achieved according to the invention by a method for manufacturing a pump device from a construction kit, in particular a construction kit according to the preceding explanations, wherein a required pump capacity of the pump device is determined, pump cartridges required to achieve the pump capacity are selected from a set of pump cartridges and a drive unit being selected, which has a drive capacity required to drive the pump cartridges.

This method has the advantages already explained in connection with the construction kit according to the invention.

An advantageous variant envisages the pump cartridges being selected from the set of pump cartridges according to the delivery volume achievable with the pump cartridges. For example, pump cartridges are selected, which have the lowest delivery volume which exceeds the required delivery volume. This is advantageous since the pump cartridges can work very efficiently in this manner.

A favourable variant envisages the pump cartridges being selected from the set of pump cartridges according to the delivery head achievable with the pump cartridges. A plurality of identical pump cartridges can be selected or pump cartridges which differ in the delivery head or the achievable pressure, in particular a combination of a pump cartridge and an empty cartridge is possible. In this manner, in terms of the required delivery volume, an optimised combination of pump cartridges can be selected, which achieve the required delivery volume so that the pump cartridges can work efficiently.

A particularly advantageous variant envisages the drive unit being selected according to the rotational speed required for the required delivery head. The pressure generation of the pump cartridges is dependent on the rotational speed such that the rotational speed of the drive unit, the delivery head and the pressure are adaptable.

A favourable possibility envisages the drive unit being selected according to the torque required for the required delivery volume. The torque that is required to drive the pump cartridges is generally dependent on the delivery volume. A drive unit can thus be selected which is optimised for the required torque.

An advantageous possibility envisages the pump cartridges being positioned at a receiving region of the drive unit after the pump cartridges and the drive unit are selected. The pump cartridges are positioned at the receiving region of the drive unit by the pump cartridge being threaded via a drive shaft of the drive unit and being slid along said drive shaft to a cartridge connection of the drive unit.

The pump cartridge is guided in this manner during positioning such that correct positioning is simplified.

A particularly favourable possibility envisages no further elements having to be inserted into the drive unit for positioning the pump cartridges or the empty cartridges. This is advantageous since a possible source of error is avoided when installing the pump device.

A particularly advantageous possibility envisages a terminal section being placed on the drive unit after positioning the pump cartridges at the receiving region of the drive unit such that the connecting section encloses the pump cartridges in the drive unit. The pump cartridges are held in the pump device in their working position by the connecting section.

It is advantageous for the connecting section to be fixed on the drive unit by at least one fastening element. The pump device is thus held together since the connecting section encloses the pump cartridges in the receiving region of the drive unit and the connecting section itself is fixed on the drive unit.

The at least one fastening element can for example be based on a materially-bonded connection by adhering or welding, frictional connection, by a screw connection or another positive-locking connection or similar.

It is favourable for a retaining nut to be screwed on the securing section of a central anchor after placing the connecting section on the drive unit. The problem of tilting is thus reduced since the thread diameter is reduced in comparison to a thread which is formed in the outer wall of the pump device.

It is particularly advantageous that no further elements have to be inserted into the drive unit to assemble the pump device aside from the pump cartridges or the empty cartridges. For this purpose, the pump cartridges have all required elements such as seals and bearings. This solution is advantageous since it is virtually impossible during assembly to forget a component since only the pump cartridges have to be inserted.

It is favourable for the pump cartridges to comprise all elements that are required for a pump stage or a group of pump stages such that no loose elements are required.

It is particularly advantageous for the differently designed pump cartridges to have a colour coding. A fitter can thus easily identify the required pump cartridges.

It is particularly advantageous for the pump cartridges to have an installation position securing means. The installation position securing means ensures that the pump cartridges cannot be installed incorrectly, for example on the head. The installation position securing means for example has an asymmetric arrangement of grooves in the drive shaft.

The solution according to the invention enables the pump devices to be configured/installed for an application in a central warehouse or a distribution centre, at a dealer or directly at the point of use. As a result, the required storage space at the dealer, which is required to cover the full spectrum of requirements, can be significantly reduced.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Further preferred features and/or advantages of the invention are the subject matter of the following description and graphic illustration of the numerous embodiments.

In the drawings:

FIG. 1 shows a perspective view of a first embodiment of a pump device, wherein positioning in a borehole is indicated;

FIG. 2 shows a sectional illustration of the pump device according to FIG. 1 in the plane AA;

FIG. 3 shows a detail enlargement of the region B according to FIG. 2;

FIG. 4 shows a perspective partial sectional illustration of the region B;

FIG. 5 shows a detail enlargement of the sectional illustration from FIG. 2 of the pump device with a drive section, a suction section and a pump section;

FIG. 6 shows a perspective partial sectional illustration of a pump section of the pump device according to FIG. 1;

FIG. 7 shows a detail enlargement of the sectional illustration of the pump device according to FIG. 2, wherein two pump cartridges are arranged in a pump section;

FIG. 8 shows a detail enlargement of the region C according to FIG. 2, wherein a pump cartridge is illustrated in a pump section;

FIG. 9 shows a perspective partial illustration of a pump section in which two pump cartridges are arranged;

FIG. 10 shows a perspective partial illustration of a pump section of the pump device, wherein pump cartridges are illustrated without outer wall;

FIG. 11 shows a perspective illustration of two pump cartridges, wherein an outer wall is faded out;

FIG. 12 shows a perspective partial sectional illustration of a pump cartridge;

FIG. 13 shows a perspective partial sectional illustration of an empty cartridge;

FIG. 14 shows a detail enlargement of the sectional illustration from FIG. 2 which shows a connecting section;

FIG. 15 shows a detail enlargement of the region D from FIG. 14;

FIG. 16 shows a perspective illustration of a connection device, wherein a connecting section is not illustrated for better clarity;

FIG. 17 shows a sectional illustration of a drive unit;

FIG. 18 shows a sectional illustration of a second embodiment of a pump device;

FIG. 19 shows a detail enlargement of the region E of the sectional illustration according to FIG. 18; and

FIG. 20 shows a detail enlargement of the region F of the sectional illustration according to FIG. 18.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary embodiment of a pump device 10 (FIG. 1) has a head section 12, a drive section 14, a pump section 16 and a connecting section 18 which follow one another in an axial direction 19.

The pump device 10 has an outer wall 13 which extends from the head section 12 to the connecting section 18. For example, the outer wall 13 is designed substantially cylindrically at least in sections and/or is arranged coaxially to a main axis 11 of the pump device 10.

The head section 12 has a cross-section 20, which reduces from a connection end 22 to a peak 24 opposite the connection end 22, in particular repeatedly and rotationally-symmetrically towards the main axis 11.

The cross-section 20 in particular has a curved contour, for example a circular contour.

The tapering of the cross-section 20 is repetitive and increases in proximity to the peak 24 such that an edge-free rounded shape 26 of the head section 12 is present.

The head section 12 also has one or a plurality of, for example, eight reinforcement ribs 28 which extend from an outer wall 30 (which is in particular part of the outer wall 30) of the head section 12 inwards to an inner (wooden) cylinder 32. These ribs increase the mechanical stiffness of the head section 12.

The head section 12 also has, in the region of the connection end 22, at least one connection element 34 and for example four connection elements 34 by means of which the head section 12 is held on the drive section 14.

The head section 12 can for example be held on the drive section 14 by a screw connection, adhesive, riveting or flanging.

The head section 12 is held on a base element 36 of the drive section 14. To this end, the base element 36 has counter elements 38 for the connection elements 34 of the head section 12.

The base element 36 has an external, in particular cylindrical wall-shaped outer section 40 extending in the axial direction 19. The outer section 40 has, at its side facing away from the head section 12, a tapered region 41, wherein a recess 43 is formed at the transition to the tapered region 41 at the inside of the outer section 40 (FIG. 5).

The outer section 40 merges, at its side facing the head section 12, into a base section 42, which extends from the outer section 40 inwards to a central opening 44. The central opening 44 is located on the main axis 11. A region 46 of the base element 36 located at the central opening 44 is closer to the head section 12 in the axial direction 19 than a region 48 of the base section 42 abutting on the outer section 40.

The base section 42 for example has the shape of a blunt cone section.

A retaining device 50 is arranged in the central opening 44 by means of which an anchor 52, in particular a central anchor 52, is held, which extends from the drive section 14 through the pump section 16 into the connecting section 18.

Further details on the central anchor 52 are explained below.

The retaining device 50 is designed cylindrically for example and extends from the region 46 of the base section 42 abutting on the central opening 44 in the axial direction 19 away from the head section 12.

The retaining device 50 is designed for connecting to the anchor 52.

One or a plurality of electrical conductors 56 is guided through the base section 42 of the base element 36 which are for example part of an electrical supply means 58 or an electrical connecting line 60 for a drive 62 of the pump device 10.

A guide device 64 is assigned to the electrical conductors 56, which encloses the electrical conductors 56 at least in sections.

The electrical conductors 56 of the electrical supply means 58 and the electrical connecting line 60 are connected to a motor controller 66 (FIG. 3).

The motor controller 66 is arranged adjacent to the base element 36 between the base element 36 and the reinforcement ribs 28 in a transition region 68 between the drive section 14 and the head section 12.

The electrical connecting lines 60 connect the motor controller 66 to windings 70 of at least one electric motor 72 of the drive 62.

The motor controller 66 has for example a motor regulator for an electronically commuted synchronous motor.

The electric motor 72 has for example an internal stator 74 with the windings 70 and a rotor 76. The stator 74 of the motor 72 has a central through-opening 94 through which the central anchor 52, the electrical supply means 58 and a hollow shaft 92 are guided. The stator 74 is arranged on a motor base element 80 and is held thereon in a torque-proof manner.

The motor base element 80 has a flat base section 82. The base section 82 is in particular designed in a circular shape and has an opening 84 located coaxially to the main axis 11.

At its outer side, the base section 82 merges into a first, in particular cylindrical wall-shaped outer wall 86, which extends in the axial direction 19 in the direction of the head section 12 and has a recess 88, which extends radially outwards (transverse to the main axis 11). It then merges into a second, in particular cylindrical wall-shaped outer wall 90, which extends back in the axial direction 19 in the direction of the head section 12.

The second outer wall 90 abuts on the outer section 40 of the base element 36. The second outer wall 90 abuts on the outer section 40 in the tapered region 41 of said outer section 40, wherein the second outer wall 90 is supported in the axial direction 19 on the recess 43 of the outer section 40.

The second outer wall 90 is held on the base element 36 in a torque-proof manner, for example by a materially-bonded connection or a positive-locking connection.

The central anchor 52, the electrical supply means 58 and the hollow shaft 92 run through the opening 84 of the base section 82.

In the drive section 14, the pump device 10 has a first mounting device 95 by means of which the hollow shaft 92 is rotatably mounted. The first mounting device 95 has for example a radial ring bearing 36, which is arranged inside a central opening 94 of the stator 74 and which mounts the hollow shaft 92.

The radial ring bearing 96 is arranged adjacent to the motor base element 80. The radial ring bearing 96 is for example a slide bearing or a roller bearing.

The electric motor 72 has the rotor 76 provided with permanent magnets. It is for example designed as an external rotor and has in particular a bell shape.

The permanent magnets are for example ferrite magnets or rare-earth magnets.

The rotor 76 has for example a cylindrical wall-shaped support section 98 on the inside of which sector-like permanent magnets 100 are arranged. The support section 98 surrounds the stator 74.

The support section 98 merges, at a side facing away from the head section 12, into a circular base section 102, which extends from the support section 98 to a connection section 104.

The connection section 104 extends from the circular base section 102 in the axial direction 19 in the direction of the connecting section 18. The connection section 104 in particular has a cylindrical wall.

The rotor 76 is held at an inside 106 of the connection section 104 on the hollow shaft 92 and is fixed thereto. The rotor 76 is connected to the hollow shaft 92 in a torque-proof manner and fixedly in the axial direction 19.

The drive section 14 also comprises a terminal element 108 (for example FIG. 4, 5), which seals the drive section 14 in a fluid-tight manner. The terminal element 108 in particular has a cylindrical wall-shaped outer wall 110 which abuts on the outer wall 13 of the pump device 10.

The outer wall 110 of the terminal element 108 merges, at its side facing the electric motor 72, into a cover section 112 which extends from the outer wall 110 radially inwardly and in the axial direction away 19 from the electric motor 72, wherein the cover section 112 is located at an (acute) angle to the main axis 11.

The cover section 112 has a central opening 114 at the main axis 11 through which run the central anchor 52, the electrical supply means 58 and the hollow shaft 92.

The terminal element 108 also has a cylindrical wall-shaped seal support section 116 at which a radial seal 118 is arranged or formed.

The radial seal 118 seals the transition between the terminal element 108 and the hollow shaft 92. The radial seal 118 is designed such that a rotation of the hollow shaft 92 (around the rotational axis coaxially to the main axis 11) is possible.

The terminal element 108 produces a sealed region 127 (FIG. 5), which is sealed in a fluid-tight manner with respect to the flowing delivery fluid (indicated in FIG. 5 with the reference numeral 126).

A suction section 120 extends from the terminal element 108 in the axial direction 19 in the direction of the connecting section 18 to an axial seal support 122.

In the region of the suction section 120, the outer wall 13 of the pump device 10 has a plurality of suction openings 124. Fluid to be pumped (delivery fluid) 126 can be suctioned through the suction openings 124 by the pump device 10.

The axial seal support 122 has an in particular cylindrical outer wall 128, which abuts on the outer wall 13 of the pump device 10 and is held thereon. The outer wall 128 of the axial seal support 122 can for example be held by a materially-bonded connection or positive-locking connection on the outer wall 13 of the pump device 10.

The outer wall 128 of the axial seal support 122 merges, at its side facing the connecting section 18, into a recess 132 forming a sealing surface 130 (FIG. 8). At its inside, the recess 132 merges into a securing section 134, which extends from the recess 132 in the axial direction 19 in the direction of the connecting section 18.

A seal receiving region 136 is arranged between the recess 132 and the securing section 134. A circular axial seal 138 is arranged in the seal receiving region 136, said circular axial seal resting on the sealing surface 130.

The axial seal 138 is pressed by a sealing surface 140 of a pump cartridge 142 against the sealing surface 130.

The securing section 134, on the one hand, ensures that the axial seal 138 cannot fall radially inwards and, on the other hand, that the axial seal 138 is not crushed.

The pump cartridge 142 has a shape, which is determined by the outer wall 13 of the pump device 10 and an inlet-side base 144 and an outlet-side base 146 (FIG. 8). The pump cartridge 142 in particular has a substantially cylindrical outer shape.

Coaxially to the outer wall 13 of the pump device 10, the pump cartridge 142 has a central opening 148 at the main axis 11 through which run the central anchor 52, the electrical supply means 58 and the hollow shaft 92.

The pump cartridge 142 has a housing 147, which comprises an outer wall 143, the inlet-side base 144 and the outlet-side base 146.

The pump cartridge 142 is divided for example into four sections, which are arranged consecutively in the axial direction 19 (see FIG. 8).

A first section 150 is arranged adjacent to a first connecting side 151 of the pump cartridge 142 and is delimited in the axial direction 19 by the inlet-side base 144 and a first intermediate base 152 and radially outwards by the outer wall 143 and radially inwards by the central opening 148.

The inlet-side base 144 has a circular flat wall 154, which extends from the outer wall 143 radially inwards to a sealing section 156. The sealing surface 140 of the pump cartridge 142 is arranged at the side of the circular flat wall 154 that faces the drive section 12 adjacent to the outer wall 143.

The first connecting side 151 comprises the inlet-side base 144, the sealing surface 140, an axial suction opening 164 and the sealing section 156.

The sealing section 156 has a cylindrical shape. It has, on the inside, a sealing surface 158 on which a radial seal 160 is arranged. The first axial suction opening 164 of the pump cartridge 142 extends between the radial seal 160 and an inner sleeve 162.

The first axial suction opening 164 forms a circular passage from the suction section 120 of the pump device 10 into the pump cartridge 142, in particular directly into the first section 150 of the pump cartridge 142.

The inner sleeve 162 extends over the entire axial height of the pump cartridge 142. The inner sleeve 162 is held on the hollow shaft 92 in a torque-proof manner to transfer a rotational movement. The inner sleeve 162 is slidable along the hollow shaft 92 in the axial direction 19.

A connection between inner sleeve 126 and hollow shaft 92 can for example be established by a positive-locking connection by means of grooves 165, which are embedded in the hollow shaft, and springs 167, which are arranged on the inner sleeve.

Installation security 171 can be achieved by an arrangement of the grooves 165 and springs 167 that is asymmetric in the circumferential direction by means of which it is ensured that the pump cartridge 142 is correctly installed.

The first section 150 of the pump cartridge 142 comprises a first pressure generation region 166, which is delimited by the inlet-side base 144, by the inner sleeve 162, by the first intermediate base and by a first radial partition wall 168, which has a cylindrical shape.

The pump cartridge 142 has at least one pump element 169 to generate a pressure differential. For example, the pump element 169 has a first impeller 170. Said impeller is arranged in the first pressure generation region 166 and is held on the inner sleeve 162.

The first impeller 170 has a first wall 172 and a spaced second wall 174, wherein the first wall 172 and the second wall 174 have a substantially constant distance to one another (FIGS. 8, 12).

The first wall 172 has an inner cylindrical section 176 by means of which the first impeller 170 is held on the inner sleeve 162. The cylindrical section 176 extends from the axial suction opening 164 in the axial direction 19 in the direction of the connecting section 18 into a curved transition section 178 in which the first wall 172 of the first impeller 170 is inclined outwards and merges into a support section 180.

The support section 180 extends from the transition section 178 outwards into proximity with the first radial partition wall 168. For example, the support section 180 extends substantially perpendicular to the axial direction 19 or substantially conically outwards.

The second wall 174 of the first impeller 170 has a cylindrical section 182, which extends from the axial suction opening 164 of the pump cartridge 142 in the axial direction 19 in the direction of the connecting section 18 until it merges into a curved transition section 184.

The cylindrical section 182 abuts on the radial seal 160 such that a distance 186 is located between the cylindrical section 182 of the second wall 174 and the cylindrical section 176 of the first wall 172.

The first impeller 170 has a suction nozzle 187 through which fluid 126 to be pumped is suctioned to the first impeller 170 (FIG. 12). The suction nozzle 187 is arranged between the cylindrical section 176 of the first wall 172 and the cylindrical section 182 of the second wall 174.

The suction nozzle 187 has a suction surface 189 through which the fluid 126 to be pumped is suctioned into the first impeller 170. The suction surface 189 is circular and extends between the cylindrical section 176 of the first wall 172 and the cylindrical section 182 of the second wall 174.

The curved transition section 184 of the second wall 174 merges into a support section 188 of the second wall 174.

The curved transition section 184 of the second wall 174 has a smaller radius than the curved transition section 178 of the first wall 172. As a result, the distance between the first wall 172 and the second wall 174 even in the region of the curved transition sections 184 and 178 is roughly the same as the distance 186 between the first wall 172 and the second wall 174 in the region of the axial suction opening 164.

The support section 188 of the second wall 174 extends from the curved transition section 184 of the second wall 174 radially outwards into proximity with the first radial partition wall 168. For example, the support section 188 extends substantially perpendicularly to the axial direction 19 or substantially conically outwards.

The support section 188 of the second wall 174 runs substantially parallel to the support section 180 of the first wall 172.

Blade elements 190 are arranged between the first wall 172 and the second wall 174 of the impeller 170, said blade elements extending between the first wall 172 and the second wall 174 of the first impeller 170.

The blade elements 190 extend substantially perpendicular to the support section 180 and the support section 188. The blade elements 190 in particular extend in a spiral shape radially outwards.

The blade elements 190 form channels 192 in the first impeller 170 between the first wall 172 and the second wall 174, which extend from the suction nozzle 187 to a radial discharge opening 194.

The radial discharge opening 194 is circular and is determined by the distance 188 between the support section 188 of the second wall 174 and the support section 180 of the first wall 172 in proximity to the first radial partition wall 168.

When the inner sleeve 162 is rotated around the main axis 11 of the pump device 10, the first impeller 170 then likewise rotates around the main axis 11 of the pump device 10. The fluid 126 to be pumped, which is located in the first pressure generation region 166, is set into rotation by the blade elements 190 between the first wall 172 and the second wall 174.

The centrifugal force generated by the rotation presses the fluid 126 to be pumped radial outwards, whereby it is suctioned into the axial suction opening 164 into the first impeller 170 and discharges back through the radial discharge opening 194.

The first radial partition wall 168 has one or a plurality of output openings 196 through which a fluidically-effective connection is formed between the first pressure generation region 166 and at least one first fluid channel 198. The output openings 196 extend into the circumferential direction only in sections.

The at least one fluid channel 198 connects the first pressure generation region 166 to a first return region 200, which is arranged in a third section 202 of the pump cartridge 142.

The first fluid channel 198 extends in the first section 150 of the pump cartridge 142 between the first radial partition wall 168 and the outer wall 143 of the pump cartridge 142 and in a second section 228 of the pump cartridge 142 between a second radial partition wall 212 and the outer wall 143 of the pump cartridge 142 in the axial direction 19, wherein the at least one first fluid channel 198 extends in the circumferential direction only in sections such that installation space is provided in the region between the first radial partition wall 168 and the outer wall 143 of the pump cartridge 142 and of the first radial partition wall 168 and the second radial partition wall 212 in which additional fluid channels can for example be arranged.

The at least one fluid channel 198 extends both in the axial direction 19 and in the circumferential direction such that a screw-shaped formation of the first section 150 to the third section 202 is given. The screw-shaped course is not necessarily completely circumferential; for example it forms an angle of 90°.

The first return region 200 extends in the radial direction from the outer wall 143 of the pump cartridge 142 and the inner sleeve 162 of the pump cartridge 142 and in the axial direction 19 between a second intermediate base 206 and a third intermediate base 208.

The second intermediate base 206 has a circular intermediate wall 210, which extends from the second radial partition wall 212 radially inwards to a cylindrical wall-shaped sealing section 214, which has, on its inside, a sealing surface 216. A radial seal 218 is arranged abutting on the sealing surface 216.

A circular axial suction opening 220 is arranged between the inside of the radial seal 218 and the inner sleeve 162. The axial suction opening 220 provides a fluidically-effective connection from the first return region 200 to a second pressure generation region 222.

The at least one fluid channel 198 and the first return region 200 form a fluid passage 204 between the output opening 196 of the first pressure generation region 166 and the axial suction opening 220 of the second pressure generation region 222.

A second pump element 223 is arranged in the second pressure generation region 222, said second pump element comprises a second impeller 224, which is designed and arranged so as to be mirror-inverted to the first impeller 170. The elements of the second impeller 224 are provided with the same reference numerals as the corresponding elements of the first impeller 170.

A mirror plane 226 runs perpendicular to the main axis 11 and between the first pressure generation region 166 and the second pressure generation region 222.

The mirror-inverted arrangement of the second impeller 224 to the first impeller 170 inside the pump cartridge 142 leads to the axial thrusts 225 acting on the impellers 170 and 224 being offset by the pumping of the fluid 126 to be pumped.

The axial thrust 225 acting on the impeller 170 results substantially from the generated pressure differential multiplied by the area of the suction surface 189 of the suction nozzle 187. The same applies to the axial thrust that acts on the second the second impeller 224.

No axial forces or small axial forces are transferred to the hollow shaft 92 by the pump operation such that it does not have to be axially secured/mounted. The axial centring of the hollow shaft 92 can for example be achieved solely by the magnetic centring forces of the electric motor 72.

The second pressure generation region 222 is arranged in a second section 228 of the pump cartridge 142. The second pressure generation region 222 extends in the axial direction 19 from the first intermediate base 152 to the second intermediate base 206 and in the radial direction from the inner sleeve 162 to the second radial partition wall 212.

The second radial partition wall 212 has at least one output opening 230, which connects the pressure generation region 222 to at least one second fluid channel 232 in a fluidically-effective manner.

The at least one second fluid channel 232 is arranged offset in the circumferential direction to the at least one first fluid channel 198.

The at least one second fluid channel 232 connects the second section 228 of the pump cartridge 142 to a fourth section 234 of the pump cartridge 142.

The fourth section 234 is arranged adjacent to a second connecting side 241 of the pump cartridge 142.

The fourth section 234 comprises a return and outlet region 236, which extends in the radial direction between the outer wall 143 of the pump cartridge 142 and the inner sleeve 162 and extends in the axial direction 19 between the third intermediate base 208 and the outlet-side base 146.

The outlet-side base 146 has an outer circular wall section 238, which merges, on its inside, into a cylinder wall-shaped securing section 240. The outer circular wall section 238 has, at its side facing the connecting section 18, an axial sealing surface 242 on which an axial seal 244 is arranged.

The securing section 240 prevents the axial seal 244 slipping radially inwards from the axial sealing surface 242 and the axial seal 244 from being crushed.

The securing section 240 of the outlet-side base 146 merges into a circular flat inner wall section 246.

The inner wall section 246 extends from the securing section 240 radially inwards up to a radial distance from the main axis 11 of the pump device 10, which corresponds to the radial distance of the outer surface of the sealing section 156 of the inlet-side base 144 from the main axis 11 of the pump device 10 such that an additional structurally-identical pump cartridge 142 can be placed on the pump cartridge 142 and it can engage flush into an outlet opening 248, which is arranged in the outlet-side base 146.

The second connecting side 241 of the pump cartridge 142 in particular comprises the outlet-side base 146, the securing section 240, the axial sealing surface 242, the axial seal 244 and the circular inner wall section 246. The second connecting side 241 and the first connecting side 151 are designed complementary to one another.

Fluid to be pumped (delivery fluid) 126 is suctioned into the first pressure generation region 166 through the axial suction opening 164 during the operation of the pump cartridge 142, set into rotation there by the impeller 170, whereby it discharges through the radial discharge opening 194 out of the impeller 170.

From there, the fluid 126 to be pumped flows through the at least one output opening 196 into the at least one first fluid channel 198.

The fluid 126 to be pumped is directed through the at least one first fluid channel 198 into the first return region 200 into which the fluid 126 to be pumped is returned radially inwards.

The fluid 126 to be pumped is suctioned at the inside of the return region 200 into the second suction opening 220 and directed through this into the second pressure generation region 222.

The fluid 126 to be pumped enters the second impeller 224 and is set into rotation by the impeller, whereby it enters a fluid channel 232 through a second radial discharge opening of the second impeller 224 through at least one output opening 230 of the second radial partition wall 212. The fluid channel 232 directs the fluid 126 to be pumped into a return and outlet region 236, which is arranged in the fourth section 234 of the pump cartridge 142.

Lastly, the fluid to be pumped leaves the pump cartridge 142 through the outlet opening 248.

The outlet opening 248 merges directly into an axial suction opening 164 at a further pump cartridge 142′.

Owing to the design of the pressure generation regions 166 and 222, the distance 186 between the first wall 172 and the second wall 174 of the impellers 170 and 224 can be varied. As a result, it is possible to use pump cartridges with a different pump capacity which have the same outer dimensions.

The connecting section 18 is arranged adjacent to the further pump cartridge 142′.

A particular form of the pump cartridge is an empty cartridge 249 (FIG. 13), which can be arranged alternately to the further pump cartridge 142′ or to the first pump cartridge 142.

The empty cartridge 249 has the same elements required for the installation in the pump device 10 as the pump cartridge 142, 142′ such that one of the pump cartridges 142, 142′ can be interchanged with the empty cartridge 249.

The empty cartridge 249 in particular has the same diameter and the same height as the pump cartridge 142, 142′ and a sealing surface 140 an inner sleeve 162 a further axial sealing surface 242 on which an axial seal 244 is arranged, which is secured by a securing section 240.

The empty cartridge 249 also has a fluid passage 251, which extends in the axial direction over the entire length of the empty cartridge 249 from a suction opening 164 to an outlet opening 230 such that the fluid 126 to be pumped can flow unaffected through the empty cartridge 249.

The pump capacity of the pump device 10 can be adapted to the given requirements for example by reducing the achievable pressure by means of exchanging a pump cartridge 142, 142′ with an empty cartridge 249.

The connecting section 18 has a termination device 250 (see FIGS. 14, 15), which has a circular sealing surface 252, which is facing the second pump cartridge 142′ and on which the axial seal 244 rests in order to form a fluid-tight transition between the axial sealing surface 242 of the pump cartridge 142; 142′ and the sealing surface 252 of the termination unit 250.

The circular sealing surface 252 comprises a central opening 254 through which the fluid 126 to be delivered is pumped into the connecting section 18. From there, the fluid 126 to be pumped is directed via one or a plurality of fluid channels 256 to a central fluid discharge opening 258. The central fluid discharge opening 258 is arranged coaxially to the main axis 11 of the pump device 10. The central fluid discharge opening 258 is for example designed with an inner thread such that a connection 259 for example a hose or tube connection 259 is fixable.

The fluid channels 256 direct the fluid to be pumped around a fixing and mounting device 260 such that it can be arranged centrally on the main axis 11 without the flow of the fluid 126 to be pumped being impeded.

The fixing and mounting device 260 has an upper radial ring bearing 262 by means of which the hollow shaft 92 is mounted.

The upper radial ring bearing 262 has for example a slide bearing or a ball bearing.

The upper radial ring bearing 262 is arranged in a support section 264 of the fixing and mounting device 260 and mounts the hollow shaft 92.

The support section 264 is held on an outer wall 268 of the connecting section 18 by a plurality of reinforcement ribs 266.

The reinforcement ribs 266 extend in the radial and axial direction from the support section 264 to the outer wall 268 such that a rotationally and translationally-fixed connection is formed between the support section 264 and the outer wall 268.

The central anchor 52 runs through the support section 264 in the connecting section 18. A securing section 265 of the central anchor 52 engages through the support section 264.

The transition between hollow shaft 92 and the support section 264 is sealed in a fluid-tight manner by a radial seal 263, which is arranged in the support section 264 adjacent to the radial ring bearing 262.

A radial seal 270 is arranged in the axial direction 19 viewed to the side of the support section 264 opposite the radial ring bearing 262, said seal sealing a transition between the central anchor 52 and the support section 264 in a fluid-tight manner. A region 271 is formed between the radial seal 270 and the radial seal 263, which is not washed around by fluid 126 to be pumped.

The central anchor 52 extends from the base section 42 of the drive section 14 along the main axis 11 of the pump device 10 through the remaining drive section 14 through the pump section 16 into the connecting section 18.

The securing section 265 of the central anchor 52 has for example an (outer) thread. A retaining nut 272 is screwed on this thread such that the support section 264 is pressed in the axial direction (in the direction of the head section 12 of the pump device 10).

Instead of the retaining nut 272, other fastening elements 273 could also be used, for example based on a materially-bonded connection by adhering or welding, frictional connection, other positive-locking connection or similar.

The central anchor 52 is held on the base section 42 of the drive section 14 by the retaining device 50 and is held at its other end on the support section 264 by the retaining nut 272. The central anchor 52 thereby holds the drive section 14, the pump section and the connecting section 18 of the pump device 10 together.

The hollow shaft 92 acts as the drive shaft 91 in the pump device and transmits the drive power of the electric motor 72.

The hollow shaft 92 extends from the motor base element 80 through the drive section 14 through the pump section 16 into the connecting section 18.

The hollow shaft 92 is mounted on its one side by the radial ring bearing 96 in the region of the motor 72 and on its other side by the radial ring bearing 262 on the support section 64 coaxially to the main axis 11 of the pump device 10 and coaxially to the central anchor 52.

The inner diameter of the hollow shaft 92 is greater than the outer diameter of the central anchor 52 such that a hollow cylindrical clearance 274 is formed between the central anchor 52 and the hollow shaft 92.

The electrical supply means 58 extends from the drive section 14 through the pump section 16 into the connecting section 18.

The electrical supply means 58 runs from the connecting section 18 into the drive section 14 inside of the clearance 274.

The electrical conductors 56 of the electrical supply means 58 are designed flat and in a circular arc-segmented manner such that they can be arranged on the central anchor 52.

In order to avoid electrical short-circuits, an inner insulating layer 276 is arranged between the electrical conductors 56 and the anchor 52, in particular the central anchor 52 and a second outer insulating layer 278 is arranged on the outside of the electrical conductors 56.

There is clearance between the outer insulating layer 278 and the inner wall of the hollow shaft 92 such that contact of the hollow shaft 92 with the outer insulating layer 278 is excluded during normal operation.

An electrical connection device 280 is arranged inside the support section 264, said electrical connection device connecting the electrical conductors 56 of the electrical supply means 58 to an electric connection 282 of the pump device 10.

The electric connection device 280 is arranged in the regions 271 not washed by the fluid 126 to be pumped such that the electrical supply means 58 does not come into contact with the fluid 126 to be pumped.

Electrical insulation of the electric connection device 280 is not required inside the region 271 not washed by fluid 126 to be pumped.

The electric connection device 280 has a plurality of, for example three contact fingers 281 by means of which an electric contact is established with the electrical conductors 56 of the electrical supply means 58 (FIG. 16).

The contact fingers 281 have spring elements, which are mechanically tensioned when a unit of the central anchor 52, the electrical conductors 56 of the electrical supply means 58 and the hollow shaft 92 is arranged in the support section 264.

Simple installation of a plurality of pre-installed units is possible with the design of the pump device 10 described above.

For example, a drive unit 284, which has the drive section 14, the outer wall 13 of the pump device 10, the central anchor 52 and the hollow shaft 92 with the electrical supply means 58 running therein, can be pre-installed such that a receiving region 286 is formed in which a plurality of, for example two pump cartridges 142, 142′ can be received.

The axial seal support 122 and the axial seal 138 form a cartridge connection 287. The cartridge connection 287 is designed complementary to the first connecting side 151 of the pump cartridge 142.

The cartridge connection 287 enables a fluidically-effective connection of the suction section 120 to the suction opening 164 of the pump cartridge 142.

The installation of the two pump cartridges 142, 142′ into the receiving regions 286 can take place by simply inserting the pump cartridges 142.

In order to close the pump device 10, the connecting section 18 is placed on one end and, with the aid of the retaining nut 272, is fixed on the central anchor 52, in particular screwed on the central anchor 52. For example, the connecting section 18 is fixed on the drive unit 284.

Since the pump device 10 is held together by the central anchor 52, only the retaining nut 272 has to be screwed on the anchor 52, in particular on the central anchor 92 in order to hold the pump device 10 together.

Simple installation of the pump device 10 is enabled by virtue of the hollow shaft 92 being mounted only in the region of the drive 62 by the radial ring bearing 96 and by the radial ring bearing 262 arranged in the connecting section 18. No additional bearings for the hollow shaft 92 thus have to be installed when inserting the pump cartridges 142, 142′.

Drive units 184 and pump cartridges 142, 142′ with varying capacities can be provided, which are interchangeable with one another such that a wide spectrum of usage requirements can be covered.

A set of pump cartridges 283 is provided, which comprises a plurality of pump cartridges 142, 142′. In particular, the set of pump cartridges 283 comprises a plurality of, for example two, identically-designed pump cartridges 142, 142′ and at least two differently-designed pump cartridges 142, 142′.

The pump cartridges 142, 142′ can be designed differently by virtue of the pump capacity of the pump cartridges 142, 142′ being different, for example through the pressure differential achieved at a certain rotational speed and resulting delivery head and/or in the delivery volume achievable at a certain rotational speed. In particular, the pump capacity of a pump cartridge 142 can be different from the pump capacity of another pump cartridge 142′ by virtue of the pump cartridge 142 not having any pump capacity at all, i.e. it merely forms a fluid passage 251, which does not achieve any further pressure increase.

A plurality of drive units 284 is also provided, which have different drive capacities. The drive capacity of the drive units 284 can differ in particular in terms of the achievable rotational speed and the torque generated by the drive unit 284.

A wide spectrum of requirements, such as for example delivery head and delivery volume can be covered.

In particular, a construction kit 285 is provided, which comprises at least one set of pump cartridges 283, a plurality of drive units 284 with different drive capacities, the connecting section 18 and a fastening element 273, for example a retaining nut 272.

If the requirements for the pump device 10 are known, pump cartridges 142, 142′ that achieve the required delivery volume are selected from the set of pump cartridges 283. Furthermore, it can for example be determined whether a pump cartridge 142, 142′ connected to an empty cartridge 249 without pump capacity is sufficient or whether two or more pump cartridges are required to achieve the required delivery heads.

The achievable delivery head depends, on the one hand, on the pump cartridge 142, 142′ and on the rotational speed of the drive unit 284 such that a corresponding drive unit 284 can be selected for a given delivery head and already selected pump cartridges 142, 142′.

The selected pump cartridges 142, 142′ are inserted into the previously-selected drive unit 284 to install the pump device 10.

Insertion takes place with each of the pump cartridges 142, 142′ being slid with their inner sleeve 162 over the drive shaft 91. The drive shaft 91 guides the pump cartridge 142 coaxially into the drive unit 284 until the sealing surface 140 of the pump cartridge 142 rests on the axial seal 138 of the drive unit 284.

The second pump cartridge 142′ is inserted into the drive unit 284 accordingly such that the sealing surface 140 of the second pump cartridge 142′ rests on the axial seal 244 of the first pump cartridge 142.

After all required pump cartridges 142, 142′ are inserted into the drive unit 284, the connecting section 18 is placed on the drive unit 248. The connecting section 18 is placed on the drive unit 284 by the central anchor 52 being guided through the central opening 254 of the connecting section 18 and through the support section 262 of the fixing and mounting device 260 such that the hollow shaft 92 is mounted by way of the radial ring bearing 262 and the securing section 265 of the anchor 52, in particular the central anchor 52, protrudes over the support section 264.

The retaining nut 272 is screwed on the securing section 265 of the anchor, in particular the central anchor 52 to fix the pump device 10, therefore the anchor 52 pulls the drive section 14 to the connecting section 18.

The pulling force of the anchor 52 causes the connecting section 18 to press on the second pump cartridge 142, the second pump cartridge 142 to press on the first pump cartridge 142 and the first pump cartridge 142 to press on the cartridge connection 287 such that force is applied to the respective axial seals such that these transitions are sealed.

The axial forces occurring due to pumping, which for example act on the housing 147 of the pump cartridges 142, are therefore transferred by the anchor 52, in particular by the central anchor 52, to the connecting section 18.

The outer wall 13 of the pump device 10 therefore does not have to withstand any axial pulling forces, in particular connections, which could absorb the axial forces, between the outer wall 13 of the pump device and the connecting section 18 are not required.

Due to the central anchor 52, the outer wall 13 of the pump device 10 can be designed thinner than if the outer wall 13 of the pump device 10 had to absorb the axial forces.

Regions of the pump device 10 near the axis, in which the pressure generation is less efficient due to the impellers 170, are therefore used for the force transmission. The regions located further outside in which pressure can be generated particularly efficiently can be used for pressure generation.

Since the electrical supply means 58 runs inside the hollow shaft 92, the electrical supply means 58 runs inside a region of the pump device 10 near the axis in which the pressure generation is less effective. The omission of these regions in which the electrical supply means 58 runs is more favourable for the pressure generation than if regions near the axis had to be used for the electrical supply means 58, which then could not be used for pressure generation.

The impeller 170 and the impeller 224 are held on the same inner sleeve 262 in the axial direction 19. As a result, the axial forces acting on the impeller are added up. Due to the mirror-inverted arrangement of the impeller 170 and the impeller 224 in relation to one another, the axial forces, which act on the impellers, are directly opposed such that the addition of the axial forces is directly offset.

The arrangement of the impellers 170 and 224 in the pump cartridge 142 and the arrangement of the fluid channels 198 and 232 ensures that a pump direction parallel to the drive axis 91 is achieved in the case of the mirror-inverted arrangement of the impellers 170 and 224, wherein the two impellers 170 and 224 are connected in series in a fluidically-effective manner.

Due to the use of an electronically commuted synchronous motor as the drive 62 of the pump device 10, rotational speeds can be achieved, which are independent of the mains frequency. Since the rotational speed of the drive 62 and therefore the rotational speed of the impellers has a decisive influence on the achievable delivery head, the number of required impellers can thereby be reduced.

The region in which the impellers are arranged along the drive shaft 91 can be reduced to the extent that a mounting of the drive shaft 91 is not required in this region.

The installation of the pump device 10 is simplified since only the pump cartridges 142 have to be inserted into the drive unit 284 without radial bearings for the drive shaft 91 having to be inserted therebetween.

A second embodiment of a pump device 10 represented in FIGS. 18 to 20 differs from the first embodiment of the pump device 10 represented in FIGS. 1 to 17 in that the rotor 76 and the hollow shaft 92 have bores 290, which allow a coolant 288 to circulate inside the electric motor 72 and the hollow shaft 92.

Moreover, the second embodiment of a pump device 10 differs from the first embodiment of the pump device 10 in that, instead of a central anchor 52, a tube 292 is guided in the hollow shaft 92 and in that the hollow shaft 92 is mounted in the connecting section 18 against the tube 292 and in that the bearing is sealed off with respect to the fluid 126 to be pumped.

The coolant 288 comprises for example a water-glycol mixture.

The bores 290 are arranged in the hollow shaft 92 in the region of the motor 72 and generate a fluidically-effective connection between the interior of the hollow shaft 92 and an interior region of the electric motor 72.

The rotor 76 also has bores 290, which are arranged in the connection section 104 of the rotor 76.

In order to enable a fluidically-effective connection from the interior of the hollow shaft 92 to a region outside of the rotor 76, the bores 290 in the connection section 104 are arranged aligned with the bores 290 in the hollow shaft 92.

The region 127 sealed off with respect to the fluid 126 to be pumped is filled with coolant 288. During the operation of the pump device, the hollow shaft 92 and the rotor 76, which is also set into rotation by coolant 288, are rotated.

The coolant 288 is pumped radially outwards in the regions in which the coolant 288 contacts rotating parts.

For example in a region between the circular base section 102 of the rotor 76 and the terminal element 108 and in a channel between the rotor 76 and the stator 74.

The rotation of the coolant is slowed down in the regions in which the coolant 288 does not contact rotating parts such that the coolant 288 can flow back radially inwards in these regions in order to ensure a circulation of the coolant 288 in a coolant circuit 294.

The bores 290 now cause the coolant circuit 294 to run, on the one hand, between the stator 74 and the rotor 76 and can therefore cool the windings 70 of the stator 74, i.e. it can absorb the heat developing in the windings 70 and, on the other hand, the coolant circuit 294 runs between the rotor 76 and the outer wall 13 of the pump device 10 to which the coolant 288 can dissipate the absorbed heat to the environment via the outer wall 13 of the pump device 10.

As a result, the windings 70 of the motor 72 are effectively cooled.

The hollow shaft 92 also has bores 290, which are arranged inside the radial ring bearing 96, such that the coolant 288 can be used as a lubricant for the radial ring bearing 96.

The tube 292 inside the support section 264, viewed in the axial direction 19 from the motor 72, also has bores 290 behind the radial ring bearing 262, which provide a fluidically-effective connection between the interior of the tube 292 and the exterior of the tube 292.

As already described, coolant 288 is suctioned from the region between the tube 292 and the hollow shaft 92 and guided radially outwards in the region of the motor.

The coolant 288 is suctioned through the bores 290, which are arranged in the tube 292 behind the second radial ring bearing 262, such that the coolant 288 can also be used as a lubricant for the second radial ring bearing 262, which is arranged in the support section 264.

The coolant 288 is suctioned into the tube 292 in the region of the motor 72, directed axially through the tube 292 in the direction of the connecting section 18 and directed in the connecting section 18 through the bore 290 radially outwards into the intermediate space between hollow shaft 92 and tube 292.

Aside from this, the second embodiment of the pump device 10 represented in the FIGS. 18 to 20 is line with the first embodiment represented in FIGS. 1 to 17 in terms of structure and function, reference being made to their description above in this respect.

LIST OF REFERENCE NUMERALS

-   10 Pump device -   11 Main axis -   12 Head section -   13 Outer wall -   14 Drive section -   16 Pump section -   18 Connecting section -   19 Axial direction -   20 Cross-section -   22 Connection end -   24 Peak -   26 Rounded shape -   28 Reinforcement ribs -   30 Outer wall -   32 Inner cylinder -   34 Connection element -   36 Base element -   38 Counter element -   40 Outer section -   41 Tapered region -   42 Base section -   43 Recess -   44 Central opening -   46 Region -   48 Region -   50 Device -   52 Central anchor -   56 Electrical conductors -   58 Electrical supply means -   60 Electric connection line -   62 Drive -   64 Guide device -   66 Motor controller -   68 Transition region -   70 Windings -   72 Electric motor -   74 Stator -   76 Rotor -   80 Motor base element -   82 Base section -   84 Opening -   86 First outer wall -   88 Recess -   90 Second outer wall -   91 Drive shaft -   92 Hollow shaft -   94 Central opening -   95 First mounting device -   96 Radial ring bearing -   98 Support section -   100 Permanent magnet -   102 Circular base section -   104 Connection section -   106 Inside -   108 Terminal element -   110 Outer wall -   112 Cover section -   114 Lateral opening -   116 Seal support section -   118 Radial seal -   120 Suction section -   122 Axial seal support -   124 Suction opening -   126 Fluid -   127 Sealed region -   128 Outer wall -   130 Sealing surface -   132 Recess -   134 Securing section -   136 Seal receiving region -   138 Axial seal -   140 Sealing surface -   142, 142′ Pump cartridge -   143 Outer wall -   144 Inlet-side base -   146 Outlet-side base -   147 Housing -   148 Central opening -   150 First section -   151 First connecting side -   152 First intermediate base -   154 Wall -   156 Sealing section -   158 Sealing surface -   160 Radial seal -   162 Inner sleeve -   164 Suction opening -   165 Groove -   166 First pressure generation region -   167 Spring -   168 First radial partition wall -   169 Pump element -   170 Impeller -   171 Installation securing means -   172 First wall -   174 Second wall -   176 Cylindrical section -   178 Curved transition section -   180 Support section -   182 Cylindrical section -   184 Curved transition section -   186 Distance -   187 Suction nozzle -   188 Support section -   189 Suction surface -   190 Blade elements -   192 Channels -   194 Radial discharge opening -   196 Output opening -   198 First fluid channel -   200 First return region -   202 Third section -   204 Fluid passage -   206 Second intermediate base -   208 Third intermediate base -   210 Circular intermediate wall -   212 Second radial partition wall -   214 Sealing section -   216 Sealing surface -   218 Radial seal -   220 Axial suction opening -   222 Second pressure generation region -   223 Second pump element -   224 Second impeller -   225 Axial thrust -   226 Mirror plane -   228 Second section -   230 Output opening -   232 Second fluid channel -   234 Fourth section -   236 Return and outlet region -   238 Circular wall section -   240 Securing section -   241 Second connecting side -   242 Sealing surface -   244 Axial seal -   246 Inner wall section -   248 Outlet opening -   249 Empty cartridge -   250 Termination device -   251 Fluid passage -   252 Sealing surface -   254 Central opening -   256 Fluid channels -   258 Fluid discharge opening -   259 Hose or tube connection -   260 Fixing and mounting device -   262 Radial ring bearing -   263 Radial seal -   264 Support section -   265 Securing section -   266 Reinforcement ribs -   268 Outer wall -   270 Seal -   271 Region (not washed by delivery fluid) -   272 Retaining nut -   273 Fastening element -   274 Clearance region -   276 Inner insulating layer -   278 Outer insulating layer -   280 Electric connection device -   281 Contact finger -   282 Electric connection -   283 Set of pump cartridges -   284 Drive unit -   285 Construction kit -   286 Receiving region -   287 Cartridge connection -   288 Coolant -   290 Bores -   292 Tube -   294 Coolant circuit 

1.-83. (canceled)
 84. A pump device for delivering a fluid to be pumped, comprising: at least one drive, a pump element for generating a pressure differential, a connecting section and an electrical supply means, wherein the pump element is arranged between the drive and the connecting section, and a drive shaft, which is connected to the drive in a torque-proof manner, wherein the drive shaft either is or comprises a hollow shaft and the electrical supply means runs inside the drive shaft.
 85. The pump device according to claim 84, wherein a central anchor is arranged inside the hollow shaft and coaxially to the hollow shaft, the electrical supply means runs in a clearance between the central anchor and the hollow shaft, and an electrical conductor of the electrical supply means is arranged uniformly around the anchor in a circumferential direction, wherein the electrical supply means includes at least two electrical conductors.
 86. The pump device according to claim 84, wherein an inner insulating layer is arranged between electrical conductors of the electrical supply means and a central anchor, and an outer insulating layer is arranged between the electrical conductors of the electrical supply means and the hollow shaft, wherein said outer insulating layer does not contact the hollow shaft.
 87. The pump device according to claim 84, wherein the electrical supply means runs inside a tube, which runs inside the hollow shaft.
 88. A pump device for delivering a fluid to be pumped, comprising: at least one first pump element for generating a pressure differential, at least one second pump element for generating a pressure differential, wherein the first pump element and the second pump element are arranged in relation to one another and configured such that an axial thrust, which acts on the first pump element when the pressure differential is generated, is opposed to an axial thrust, which acts on the second pump element when the pressure differential is generated, wherein the second pump element is configured and arranged substantially mirror-symmetrically to the first pump element.
 89. The pump device according to claim 88, wherein the first pump element has a first impeller with a suction nozzle, the second pump element has a second impeller with a suction nozzle, and the suction nozzle of the first impeller and the suction nozzle of the second impeller face one another.
 90. The pump device according to claim 88, wherein the first pump element is arranged in a first pressure generation region, which has an axial suction opening, the second pump element is arranged in a second pressure generation region, which has an axial suction opening, the axial suction opening of the first pressure generation region and the axial suction opening of the second pressure generation region are directed in opposing directions, the first pressure generation region and the second pressure generation region are arranged adjacent to one another, the axial suction opening of the first pressure generation region and the axial suction opening of the second pressure generation region are arranged at sides of the first pressure generation region and of the second pressure generation region facing away from one another, the first pressure generation region is delimited in a radial direction outwards by a first radial partition wall, which has at least one suction opening of the first pressure generation region, the at least one suction opening is configured to establish a fluidically-effective connection from the first pressure generation region to a fluid passage, which connects the at least one suction opening of the first pressure generation region to the axial suction opening of the second pressure generation region in a fluidically-effective manner.
 91. The pump device according to claim 90, wherein at least one first fluid channel extends from the at least one suction opening of the first pressure generation region to a return region, an extension of the first fluid channel is delimited in a circumferential direction and is delimited in the radial direction outwards by a cylindrical outer wall of the pump device and inwards by the first radial partition wall and a second radial partition wall, the second pressure generation region is delimited in the radial direction outwards by the second radial partition wall, which has at least one output opening of the second pressure generation region, at least one second fluid channel extends from the at least one output opening of the second pressure generation region to a return and outlet region, and the at least one second fluid channel is delimited in the circumferential direction and arranged offset in the circumferential direction to the at least one first fluid channel.
 92. A pump cartridge for a pump device according to claim 88, wherein the first pump element and the second pump element are arranged in relation to one another and designed such that the axial thrust, which acts on the first pump element when the pressure differential is generated, is opposed to the axial thrust, which acts on the second pump element when the pressure differential is generated.
 93. A pump device for delivering a fluid, comprising: a drive, a drive shaft, and at least two pump elements, which are each configured as an impeller or comprise an impeller, the drive shaft is or has a hollow shaft, the at least two pump elements are connected to the drive shaft in a torque-proof manner in a first region of the drive shaft, and the drive shaft is mounted in a second region of the drive shaft, which is different from the first region, the hollow shaft extends from a drive section of the pump device to a connecting section of the pump device, the hollow shaft is mounted in the connecting section of the pump device, and the hollow shaft is mounted in the drive section of the pump device.
 94. The pump device according to claim 93, wherein the pump device has a first mounting device, which mounts the hollow shaft and has a fixing and mounting device, which mounts the hollow shaft, the first mounting device has at least one radial ring bearing by which the hollow shaft is mounted, and the at least one radial ring bearing is arranged inside an electric motor of the drive.
 95. The pump device according to claim 94, wherein the fixing and mounting device has at least one radial ring bearing by which the hollow shaft is mounted, and the at least one radial ring bearing of the fixing and mounting device is located inside of a support section of the fixing and mounting device, which is arranged in the connecting section of the pump device.
 96. A pump device for delivering a fluid to be pumped, comprising: a drive unit with a drive and with a drive shaft, wherein the drive shaft is or comprises a hollow shaft and an anchor for absorbing axial forces which run through the hollow shaft.
 97. The pump device according to claim 96, wherein the anchor is configured to absorb pump forces, which occur at the pump device when pressure is generated, and the anchor is arranged coaxially to a rotational axis of a pump element for generating a pressure differential.
 98. A pump device for delivering a fluid to be pumped, comprising: an outer wall, at least one drive having an electric motor with windings, wherein the electric motor is arranged in a region filled with a coolant, which comprises a coolant circuit, the coolant circuit has at least one branch, which extends at least in sections along the outer wall of the pump device, and a coolant circulation in the coolant circuit is driven during operation of the electric motor, a drive shaft comprising a hollow shaft for torque transmission between the drive and at least one pump element to generate a pressure differential, the at least one branch extending at least in sections inside the hollow shaft, and the hollow shaft having at least one bore, which provides a fluidically-effective connection from an interior of the hollow shaft to an exterior of the hollow shaft, and the at least one bore in the hollow shaft being arranged inside the electric motor, the electric motor has a rotor with a connection section by which the rotor is held on the hollow shaft, and the connection section has at least one bore, the at least one bore of the hollow shaft is aligned with the at least one bore in the connection section, at least one radial ring bearing by which the hollow shaft is mounted against a tube arranged in the hollow shaft, the tube has at least one bore, which provides a connection from an interior of the tube to an exterior of the tube, and the at least one bore of the tube is arranged behind the at least one radial ring bearing, as viewed from the at least one drive.
 99. The pump device according to claim 98, wherein the at least one radial ring bearing is arranged inside the region filled with coolant and the coolant circuit has at least one branch, which extends at least in sections along the at least one radial ring bearing.
 100. The pump device according to claim 98, wherein the pump device is configured as a borehole pump or comprises a borehole pump.
 101. A pump device for delivering a fluid, comprising: an outer wall, at least one drive, which has an electric motor with windings, at least one pump element for generating a pressure differential, a drive shaft having a hollow shaft for torque transmission between the at least one drive and the at least one pump element, the electric motor is arranged in a region filled with a coolant, which comprises a coolant circuit, wherein a coolant circulation is driven during operation of the electric motor, at least one first radial ring bearing on which the drive shaft is mounted and which is arranged inside the region filled with coolant, at least one second radial ring bearing on which the hollow shaft of the drive shaft is mounted against a tube arranged in the hollow shaft, the tube has at least one bore, which provides a connection from an interior of the tube to an exterior of the tube, the second radial ring bearing, as viewed from the at least one drive, is arranged behind the pump element, and the tube has at least one bore, which, as viewed from the at least one drive, is arranged at least one of (i) behind the second radial ring bearing, and (ii) inside of the second radial ring bearing, and wherein the coolant circuit has a branch, which extends at least in sections inside the tube.
 102. The pump device according to claim 101, wherein the hollow shaft has at least one bore, which provides a fluidically-effective connection from an interior of the hollow shaft to an exterior of the hollow shaft, and the at least one bore in the hollow shaft is arranged inside the first radial ring bearing, which is arranged inside the drive.
 103. The pump device according to claim 101, wherein the coolant circuit has at least one branch, which extends at least in sections along the outer wall of the pump device, the electric motor has a rotor with a connection section by which the rotor is held on the hollow shaft, and the connection section has at least one bore that is aligned with the bore in the connection section.
 104. The pump device according to claim 101, wherein the coolant circuit has at least one branch, which extends at least in sections along the windings of the electric motor.
 105. A construction kit for a pump device for delivering fluid to be pumped, the construction kit comprising: at least one drive unit with a drive and at least one receiving region; at least two pump cartridges positioned on the at least one receiving region and hydraulically connected to each other in series, each pump cartridge comprising a housing including a first connecting side, which has a suction opening, and a second connecting side, which has an outlet opening, wherein at least two of the pump cartridges have different pump capacities.
 106. The construction kit according to claim 105, wherein at least one of the pump cartridges comprises at least one pump element arranged in the housing to generate a pressure differential between the suction opening and the outlet opening, the at least one pump element comprises an impeller, and at least two of the pump cartridges have different pump capacities by virtue of a distance between a first wall of the impeller and a second wall of the impeller being different sizes between which the fluid to be pumped is set into rotation.
 107. The construction kit according to claim 105, wherein the drive unit has a drive shaft that extends through the receiving region, at least one of the pump cartridges has an inner sleeve, which is slidable over the drive shaft of the drive unit, the inner sleeve is held on the drive shaft in a torque-proof manner by a positive-locking connection, the inner sleeve extends over an entire height of the respective pump cartridge, and at least one of the pump cartridges has a pump element, which is held on the inner sleeve of the pump cartridge in a torque-proof manner and fixedly in an axial direction.
 108. A construction kit according to claim 105, wherein the construction kit has at least two drive units, which have different drive capacities, and the at least two drive units include different motors having different stator heights and rotor heights.
 109. A method for manufacturing the pump device of the construction kit of claim 105, comprising: determining a required pump capacity of the pump device; selecting the pump cartridges required to achieve the pump capacity from said at least two of the pump cartridges; and selecting a drive unit having a drive capacity required to drive the pump cartridges.
 110. The method according to claim 109, further comprising: positioning the pump cartridges at a receiving region of the drive unit after the pump cartridges and the drive unit have been selected such that no additional elements have to be inserted into the drive unit when positioning the pump cartridges or the empty cartridges, placing a connecting section on the drive unit after the pump cartridges have been positioned at the receiving region of the drive unit such that the connecting section encloses the pump cartridges in the drive unit, fixing the connecting section on the drive unit by at least one fastening element, and fastening a retaining nut on a securing section of a central anchor after the connecting section has been placed on the drive unit. 